Considering that there is no simple and mature analysis calculation method for fire flood front at present, on the basis of the characteristics of fire flooding, the proper tracer is chosen to monitor the gas channeling direction. Taking the field test area of fire flooding in Liaohe oilfield as an example, in the light of the fundamental idea of material balance, the new method of determining the position of combustion front for in-situ combustion has been established, six well groups have been calculated and the factors influencing fire flooding front development direction have been analyzed in the combination with the engineering geological factors. Compared to the traditional production allocation calculation method, the new method of using the tracer to assist in determining the combustion front of in-situ combustion can indicate the gas streaming directions between the wells and the gas flow from different directions more accurately, thereby avoiding the calculation error of blindly allocating gas production rate. This calculation method is more simple, convenient and feasible and the calculation results are more accurate and impressive.